add sub. and or 加法 減法...........
上傳時間： 2013-12-24
上傳用戶：ljt101007
a carrier sense multiple access with collision avoidance (CSMA/CA) based MAC protocol, called nanoMAC, suitable for low bit-rate, low-power wireless devices with high efficiency
標簽： avoidance collision multiple protocol
上傳時間： 2017-08-28
上傳用戶：小寶愛考拉
OFDM(正交頻分復用)技術實際上是MCM(Multi-Carrier Modulation，多載波調制)的一種。其主要思想是，將信道分成若干正交子信道，將高速數據信號轉換成并行的低速子數據流，調制到在每個子信道上進行傳輸。正交信號可以通過在接收端采用相關技術來分開，這樣可以減少子信道之間的相互干擾(ICI)。每個子信道上的信號帶寬小于信道的相關帶寬，因此每個子信道上的可以看成平坦性衰落，從而可以消除符號間干擾。而且由于每個子信道的帶寬僅僅是原信道帶寬的一小部分，信道均衡變得相對容
標簽： Multi-Carrier Modulation OFDM MCM
上傳時間： 2017-09-03
上傳用戶：skfreeman
Combined Processing of GPS, GLONASS, and SBAS Code Phase and Carrier Phase Measurements Lambert Wanninger, Stephan Wallstab-Freitag Geodetic Institute, Dresden University of Technology, Germany
標簽： Phase Measurements Processing and
上傳時間： 2014-01-15
上傳用戶：asasasas
Carrier Board for Gumstix Verdex Pro. Has 2 - 30A motor drivers for robotic loco motion PIC micro handles motion control. USB host signals. USB console connector AC97 audio CODEC Exapnsion headers for PIC micro.
標簽： for Carrier Gumstix drivers
上傳時間： 2014-05-29
上傳用戶：Yukiseop
元器件樣本專輯 116冊 3.03GD-sub-jy.pdf
標簽：
上傳時間： 2014-05-05
上傳用戶：時代將軍
We introduce a sub-cell WENO reconstruction method to evaluate spatial derivatives in the high-order ADER scheme. The basic idea in our reconstruction is to use only r stencils to reconstruct the point-wise values of solutions and spatial derivatives for the 2r-1 th order ADER scheme in one dimension, while in two dimensions, the dimension-by-dimension sub-cell reconstruction approach for spatial derivatives is employed. Compared with the original ADER scheme of Toro and Titarev (2002) [2] that uses the direct derivatives of reconstructed polynomials for solutions to evaluate spatial derivatives, our method not only reduces greatly the computational costs of the ADER scheme on a given mesh, but also avoids possible numerical oscillations near discontinuities, as demonstrated by a number of one- and two-dimensional numerical tests. All these tests show that the 5th-order ADER scheme based on our sub-cell reconstruction method achieves the desired accuracy, and is essentially non-oscillatory and computationally cheaper for problems with discontinuities.
標簽： 高精度格式
上傳時間： 2016-01-13
上傳用戶：ccsdcczd
Multi-carrier modulation? Orthogonal Frequency Division Multi- plexing (OFDM) particularly? has been successfully applied to a wide variety of digital communications applications over the past several years. Although OFDM has been chosen as the physical layer standard for a diversity of important systems? the theory? algorithms? and implementation techniques remain subjects of current interest. This is clear from the high volume of papers appearing in technical journals and conferences.
標簽： COMMUNICATIONS MULTI-CARRIER DIGITAL
上傳時間： 2020-05-31
上傳用戶：shancjb
Since the principle of multi-carrier code division multiple access (MC-CDMA) was simultaneously proposed by Khaled Fazel et al. and Nathan Yee et al. at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum (MC-SS) has rapidly become one of the most wide spread independent research topics on the field of mobile radio communications. Therefore, the International Workshop on Multi-Carrier Spread Spectrum (MC-SS) was initiated in the year 1997. Multi-carrier and spread spectrum systems with their generic air interface and adaptive technologies are considered as potential candidates to fulfill the requirements of next generation mobile communications systems.
標簽： Multi-Carrier Spectrum Spread 2007
上傳時間： 2020-05-31
上傳用戶：shancjb
普通GPS接收機在特殊環境下，如在高樓林立的城市中心，林木遮擋的森林公路，特別是在隧道和室內環境的情況下，由于衛星信號非常微弱，載噪比（Carrier Noise Ratio，C/No）通常都在34dB-Hz以下，很難有效捕獲到衛星信號，導致無法正常定位。惡劣條件下的定位有廣闊的發展和應用前景，特別是在交通事故、火災和地震等極端環境下，快速準確定位當事者所處位置對于降低事態損失和營救受傷者是極為重要的。歐美和日本等發達國家也都制定了相應的提高惡劣條件下高靈敏度定位能力的發展政策。而高靈敏度GPS接收機定位的關鍵在于GPS微弱信號的處理。 本課題的主要研究內容是針對GPS微弱信號改進處理方法。針對傳統GPS接收機信號捕獲中的串行搜索方法提出了基于批處理的微弱信號捕獲方法,來提高低信噪比情況下微弱信號的捕獲能力，實現快速高靈敏度的準確捕獲；針對捕獲微弱信號處理大量數據導致的運算量激增，運用雙塊零拓展(Double Block Zero Padding，DBZP)處理方法減少運算量同時縮短捕獲時間。針對傳統GPS接收機延遲鎖相環跟蹤算法提出了基于卡爾曼濾波的新型捕獲算法，減小延遲鎖相環失鎖造成的信號跟蹤丟失概率，來提高惡劣環境下低信噪比信號的跟蹤能力，實現微弱信號的連續可靠跟蹤。通過提高GPS微弱信號的捕獲與跟蹤能力，進而使GPS接收機在惡劣環境下衛星信號微弱時能夠實現較好的定位與導航。 通過擬合GPS接收機實際接收到的原始數據，構造出不同載噪比的數字信號，分別對提出的針對微弱信號的捕獲與跟蹤算法進行仿真比較驗證，結果表明，對接收機后端信號處理部分作出的算法改進使得GPS接收機可以更好的處理微弱信號，并且具有較高的靈敏度和精度。文章同時針對提出的數據處理特征使用FPGA技術對算法主要的數據處理部分進行了初步的構架實現并進行了板級驗證，結果表明，利用FPGA技術可以較好的實現算法的數據處理功能。文章最后給出了結論，通過提出的基于批處理和基于DBZP方法的捕獲算法以及基于卡爾曼濾波的信號跟蹤算法，可以有效地解決微弱GPS信號處理的難題，進而實現微弱信號環境下的定位與導航。
上傳時間： 2013-05-31
上傳用戶：cccole0605
